Macrocyclic deaza-purinones for the treatment of viral infections

ABSTRACT

This invention relates to macrocyclic deaza-purinones derivatives, processes for their preparation, pharmaceutical compositions, and their use in treating viral infections.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/781,291, filed Sep. 29, 2015, which is a 35 U.S.C. § 371nationalization of PCT application PCT/EP2014/056270 filed Mar. 28,2014, which claims priority to European patent application EP 13161865.4filed Mar. 29, 2013, each of which are incorporated herein by referencein its entirety.

SEQUENCE LISTING

The instant application contains a Sequence Listing which has beensubmitted electronically in ASCII format and is hereby incorporated byreference in its entirety. Said ASCII copy, created on Apr. 9, 2019, isnamed TIP0293USCNTI_SL.txt and is 662 bytes in size.

This invention relates to macrocyclic deaza-purinones derivatives,processes for their preparation, pharmaceutical compositions, and theiruse in treating viral infections.

The present invention relates to the use of macrocyclic deaza-purinonesderivatives in the treatment of viral infections, immune or inflammatorydisorders, whereby the modulation, or agonism, of toll-like-receptors(TLRs) is involved. Toll-Like Receptors are primary transmembraneproteins characterized by an extracellular leucine rich domain and acytoplasmic extension that contains a conserved region. The innateimmune system can recognize pathogen-associated molecular patterns viathese TLRs expressed on the cell surface of certain types of immunecells. Recognition of foreign pathogens activates the production ofcytokines and upregulation of co-stimulatory molecules on phagocytes.This leads to the modulation of T cell behaviour.

It has been estimated that most mammalian species have between ten andfifteen types of Toll-like receptors. Thirteen TLRs (named TLR1 toTLR13) have been identified in humans and mice together, and equivalentforms of many of these have been found in other mammalian species.

However, equivalents of certain TLR found in humans are not present inall mammals. For example, a gene coding for a protein analogous to TLR10in humans is present in mice, but appears to have been damaged at somepoint in the past by a retrovirus. On the other hand, mice express TLRs11, 12, and 13, none of which are represented in humans. Other mammalsmay express TLRs which are not found in humans. Other non-mammalianspecies may have TLRs distinct from mammals, as demonstrated by TLR14,which is found in the Takifugu pufferfish.

This may complicate the process of using experimental animals as modelsof human innate immunity.

For detailed reviews on toll-like receptors see the following journalarticles. Hoffmann, J. A., Nature, 426, p 33-38, 2003; Akira, S.,Takeda, K., and Kaisho, T., Annual Rev. Immunology, 21, p 335-376, 2003;Ulevitch, R. J., Nature Reviews: Immunology, 4, p 512-520, 2004.

Compounds indicating activity on Toll-Like receptors have beenpreviously described such as purine derivatives in WO 2006/117670,adenine derivatives in WO 98/01448 and WO 99/28321, and pyrimidines inWO 2009/067081.

However, there exists a strong need for novel Toll-Like receptormodulators having preferred selectivity, higher potency, highermetabolic stability, and an improved safety profile compared to thecompounds of the prior art.

In the treatment of certain viral infections, regular injections ofinterferon (IFN-alfa) can be administered, as is the case for hepatitisC virus (HCV). For more information see Fried et al. Peginterferon-alfaplus ribavirin for chronic hepatitis C virus infection, N Engl J Med2002; 347: 975-82. Orally available small molecule IFN inducers offerthe potential advantages of reduced immunogenicity and convenience ofadministration. Thus, novel IFN inducers are potentially effective newclass of drugs for treating virus infections. An example of a smallmolecule IFN inducer having antiviral effect see De Clercq, E.;Descamps, J.; De Somer, P. Science 1978, 200, 563-565.

IFN-alfa is also given in combination with other drugs in the treatmentof certain types of cancer (Eur. J. Cancer 46, 2849-57, and Cancer Res.1992, 52, 1056). TLR 7/8 agonists are also of interest as vaccineadjuvants because of their ability to induce pronounced Thl response(Hum. Vaccines 2010, 6, 322-335, and Hum. Vaccines 2009, 5, 381-394).

In accordance with the present invention a compound of formula (I) isprovided

and pharmaceutically accepted salts thereof, whereinX is oxygen, nitrogen or sulfurY represents an aromatic ring or heterocyclic ring comprising at least anitrogen, optionally substituted by one or more substituentsindependently selected from C₁₋₆alkyl, C₁₋₄alkoxy, trifluoromethyl orhalogen,Z represents C₁₋₁₀ saturated or unsaturated alkyl optionally substitutedby an alkyl or alkylhydroxyl;or Z represents C₁₋₆alkyl-NH—C(O)—C₁₋₆alkyl-, C₁₋₆alkyl-NH— orC₁₋₄alkyl-NH—C(O)—C₁₋₄alkyl-O—;or Z represents C₁₋₁₀alkyl-O— wherein said alkyl is unsaturated orsaturated and can optionally be substituted by an alkyl oralkylhydroxyl,or Z represents C₁₋₄alkyl-O—C₁₋₄alkyl- wherein said alkyl is unsaturatedor saturated and can optionally be substituted by an alkyl oralkylhydroxylor Z represents C₁₋₆alkyl-O—C₁₋₄alkyl-O— wherein said alkyl isunsaturated or saturated and can optionally be substituted by an alkylor alkylhydroxyl.

Preferred compounds having one of the following formula's according tothe invention were selected from the group of:

Part of the invention is also a pharmaceutical composition comprising acompound of formula (I) or a pharmaceutically acceptable salt, solvateor polymorph thereof together with one or more pharmaceuticallyacceptable excipients, diluents or carriers.

Furthermore to the invention belongs a compound of formula (I) or apharmaceutically acceptable salt, solvate or polymorph thereof or apharmaceutical composition above mentioned for use as a medicament.

The invention also relates to a compound of formula (I) or apharmaceutically acceptable salt, solvate or polymorph thereof or apharmaceutical composition above mentioned for use in the treatment of adisorder in which the modulation of TLR7 is involved.

The term “alkyl” refers to a straight-chain or branched-chain mostlysaturated (but in specific compounds according to the invention beingunsaturated) aliphatic hydrocarbon containing the specified number ofcarbon atoms.

The term “halogen” refers to fluorine, chlorine, bromine or iodine.

The term “alkoxy” refers to an alkyl (carbon and hydrogen chain) groupsingular bonded to oxygen like for instance a methoxy group or ethoxygroup.

Pharmaceutically acceptable salts of the compounds of formula (I)include the acid addition and base salts thereof. Suitable acid additionsalts are formed from acids which form non-toxic salts. Suitable basesalts are formed from bases which form non-toxic salts.

The compounds of the invention may also exist in unsolvated and solvatedforms. The term “solvate” is used herein to describe a molecular complexcomprising the compound of the invention and one or morepharmaceutically acceptable solvent molecules, for example, ethanol.

The term “polymorph” refers to the ability of the compound of theinvention to exist in more than one form or crystal structure.

The compounds of the invention can be present in a so-called“tautomer(s)” formation refering to isomers of organic compounds thatreadily interconvert by a chemical reaction called tautomerization. Thisreaction results in the formal migration of a hydrogen atom or proton,accompanied by a switch of a single bond and adjacent double bond.

The compounds of the present invention may be administered ascrystalline or amorphous products. They may be obtained for example assolid plugs, powders, or films by methods such as precipitation,crystallization, freeze drying, spray drying, or evaporative drying.They may be administered alone or in combination with one or more othercompounds of the invention or in combination with one or more otherdrugs. Generally, they will be administered as a formulation inassociation with one or more pharmaceutically acceptable excipients. Theterm “excipient” is used herein to describe any ingredient other thanthe compound(s) of the invention. The choice of excipient dependslargely on factors such as the particular mode of administration, theeffect of the excipient on solubility and stability, and the nature ofthe dosage form.

The compounds of the present invention or any subgroup thereof may beformulated into various pharmaceutical forms for administrationpurposes. As appropriate compositions there may be cited allcompositions usually employed for systemically administering drugs. Toprepare the pharmaceutical compositions of this invention, an effectiveamount of the particular compound, optionally in addition salt form, asthe active ingredient is combined in intimate admixture with apharmaceutically acceptable carrier, which carrier may take a widevariety of forms depending on the form of preparation desired foradministration. These pharmaceutical compositions are desirably inunitary dosage form suitable, for example, for oral, rectal, orpercutaneous administration. For example, in preparing the compositionsin oral dosage form, any of the usual pharmaceutical media may beemployed such as, for example, water, glycols, oils, alcohols and thelike in the case of oral liquid preparations such as suspensions,syrups, elixirs, emulsions, and solutions; or solid carriers such asstarches, sugars, kaolin, diluents, lubricants, binders, disintegratingagents and the like in the case of powders, pills, capsules, andtablets. Because of their ease in administration, tablets and capsulesrepresent the most advantageous oral dosage unit forms, in which casesolid pharmaceutical carriers are obviously employed. Also included aresolid form preparations that can be converted, shortly before use, toliquid forms. In the compositions suitable for percutaneousadministration, the carrier optionally comprises a penetration enhancingagent and/or a suitable wetting agent, optionally combined with suitableadditives of any nature in minor proportions, which additives do notintroduce a significant deleterious effect on the skin. Said additivesmay facilitate the administration to the skin and/or may be helpful forpreparing the desired compositions. These compositions may beadministered in various ways, e.g., as a transdermal patch, as aspot-on, as an ointment. The compounds of the present invention may alsobe administered via inhalation or insufflation by means of methods andformulations employed in the art for administration via this way. Thus,in general the compounds of the present invention may be administered tothe lungs in the form of a solution, a suspension or a dry powder.

It is especially advantageous to formulate the aforementionedpharmaceutical compositions in unit dosage form for ease ofadministration and uniformity of dosage. Unit dosage form as used hereinrefers to physically discrete units suitable as unitary dosages, eachunit containing a predetermined quantity of active ingredient calculatedto produce the desired therapeutic effect in association with therequired pharmaceutical carrier. Examples of such unit dosage forms aretablets (including scored or coated tablets), capsules, pills, powderpackets, wafers, suppositories, injectable solutions or suspensions andthe like, and segregated multiples thereof.

Those of skill in the treatment of infectious diseases will be able todetermine the effective amount from the test results presentedhereinafter. In general it is contemplated that an effective dailyamount would be from 0.01 mg/kg to 50 mg/kg body weight, more preferablyfrom 0.1 mg/kg to 10 mg/kg body weight. It may be appropriate toadminister the required dose as two, three, four or more sub-doses atappropriate intervals throughout the day. Said sub-doses may beformulated as unit dosage forms, for example, containing 1 to 1000 mg,and in particular 5 to 200 mg of active ingredient per unit dosage form.

The exact dosage and frequency of administration depends on theparticular compound of formula (I) used, the particular condition beingtreated, the severity of the condition being treated, the age, weightand general physical condition of the particular patient as well asother medication the individual may be taking, as is well known to thoseskilled in the art.

Furthermore, it is evident that the effective amount may be lowered orincreased depending on the response of the treated subject and/ordepending on the evaluation of the physician prescribing the compoundsof the instant invention. The effective amount ranges mentioned aboveare therefore only guidelines and are not intended to limit the scope oruse of the invention to any extent.

Overall Scheme in the Preparation of Final Products: Method 1

Synthesis of Intermediate B1

SOCl₂ (80 mL; 1.11 mol) was added drop wise to a mixture of G1 (19.1 g;111 mmol) in CH₂Cl₂ (230 mL) at rt. The mixture was stirred at rt for 16h. The solvent was evaporated and the residue was solubilized in CH₂Cl₂and treated with a saturated aqueous solution of NaHCO₃ until basic pH.The layers were separated and the aqueous layer was extracted withCH₂Cl₂ (twice). The combined organic layers were dried over MgSO₄,filtered and concentrated in vacuo to give 20.1 g of a brown oil. Thecrude compound was used in the next step without further purification.

Synthesis of Intermediate C1

The reaction was performed on two batches in parallel (13.6 mmol and27.1 mmol of A1).

To a solution of A1 (5.0 g; 13.6 mmol) and K₂CO₃ (3.75 g; 27.1 mmol) inacetone (100 mL) were added B1 (4.46 g; 24.4 mmol) and NaI (2.23 g; 14.9mmol) at rt. The mixture was stirred at rt for 16 h. The mixture wasfiltered and the filtrate was evaporated in vacuo to give a brown oil.The two batches were combined and purified by preparative LC (IrregularSiOH 15-40 μm, 220 g Grace, mobile phase gradient: CH₂Cl₂/EtOAc from100/0 to 80/20). The fractions containing product were combined and thesolvent was removed in vacuo to give 18.6 g of intermediate C1 (89%yield).

Synthesis of Intermediate D1

To a solution of C1 (18.6 g; 36.1 mmol) in THF (300 mL) was added anaqueous solution of NH₃ (30%) (290 mL) at rt, and the mixture wasstirred at rt for 16 h. The mixture was taken up with EtOAc andsaturated NaCl solution, the layers were separated and the organic layerwas dried over MgSO₄, filtered and the solvent was removed under reducedpressure to give 16.7 g of a yellow-orange oil. The crude was driedunder high vacuum to give 16.5 g of a sticky yellow-orange solid, whichwas used directly in the next step.

Synthesis of Intermediate E1

NaH (60% in oil) (1.75 g; 43.7 mmol) was added portion wise to allylalcohol (50 mL) at rt. The mixture was stirred at rt for 30 min beforebeing added drop wise to a solution of D1 (5 g; 11.1 mmol) in THF (124mL) at 0° C. The resulting mixture was then stirred at rt for 1 h andwas poured in saturated NH₄Cl aqueous solution. EtOAc and saturated NaClaqueous solution were added, the layers were separated and the aqueouslayer was extracted with EtOAc (once). The combined organic layers weredried over MgSO₄, filtered and the solvent was removed under reducedpressure to give a yellow oil. The crude compound was purified bypreparative LC (Irregular SiOH 15-40 μm, 120 g Grace, liquid injection,mobile phase gradient: from Heptane/EtOAc 100/0 to 50/50) to give 4.04 gof intermediate E1 as a yellow oil (79% yield).

Synthesis of Intermediate F1

The reaction was performed in 2 batches of 850 mg and 2 batches of 1 gof E1.

Herein is the procedure for one batch of 850 mg:

In a schlenk flask, a solution of E1 (0.85 g; 1.98 mmol) andchlorodicyclohexylborane (1M solution in hexane) (400 μL; 400 μmol) indichloroethane (570 mL) was stirred at 80° C. under N₂ atmosphere for 1h. Grubbs-Hoveyda catalyst 2^(nd) generation (124 mg; 198 μmol) wasadded and the mixture was stirred at 120° C. for 16 h. The mixture wasdegassed by N₂ bubbling for 10 min and further Grubbs-Hoveyda catalyst2^(nd) generation (124 mg; 198 μmol) and chlorodicyclohexylborane (1Msolution in hexane) (400 μL; 400 μmol) were added. The mixture wasstirred at 120° C. for 20 h.

The 2 batches were mixed and a ruthenium scavenger (SiliaBond DMT fromSiliCycle) (10.4 g; 6.35 mmol) was added and the mixture was stirred atrt for 20 h. The reaction mixture was filtered through a pad of celiteand the solvent was removed under reduced pressure to give a brownresidue.

The residue was combined with the residue obtained from the two batchesof 1 g of E1. The resulting brown residue was purified by preparative LC(Irregular SiOH 15-40 μm, 120 g Grace, dry loading, mobile phasegradient: from Heptane/EtOAc 100/0 to 0/100) to give 1.19 g of a brownsolid. The brown solid was further purified by preparative LC(Stationary phase: irregular bare silica 40 g, mobile phase gradient:from CH₂Cl₂/EtOAc 90/10 to 80/20) to give 705 mg of a yellow solid. Theyellow solid was further purified by achiral SFC (stationary phase:Amino 6 μm 150×21.2 mm), mobile phase: Gradient from 85% CO₂, 15% MeOHto 65% CO₂, 35% MeOH) to give 660 mg of intermediate F1 as a yellowsolid (19% yield, E isomer).

Synthesis of Final Compound 1

A mixture of F1 (570 mg; 1.42 mmol) and iron (795 mg; 14.2 mmol) in AcOH(21 mL) and water (4.2 mL) was stirred at 50° C. for 2 h. The mixturewas concentrated until dryness. DMF was added, the mixture wassonicated, heated and filtered through a pad of celite and the celitewas rinsed with hot DMF. An iron scavenger (SiliaBond Imidazole fromSiliCycle) (25.4 g; 29.5 mmol) was added to the filtrate and the mixturewas stirred at rt for 16 h. The mixture was filtered through celite, thecelite was rinsed with DMF and the filtrate was concentrated in vacuo togive 620 mg of a brown solid. The crude was purified by preparative LC(irregular SiOH, 15-40 μm, 30 g Merck, mobile phase gradient: fromCH₂Cl₂/MeOH/NH₃aq 98/2/0.2 to 85/15/1.5) to give 360 mg of finalcompound 1 as an off-white solid (75% yield).

Alternative Synthesis of Intermediate C1

At 0° C., diisopropylazodicarboxylate (DIAD) (3.0 mL, 15.0 mmol) wasadded drop wise to a mixture of A1 (3.70 g, 10.028 mmol), G1 (1.98 g,12.0 mmol) and PPh₃ (3.94 g, 15.0 mmol) in THF (70 mL). The mixture wasstirred at rt for 12 h. EtOAc and water were added. The layers weredecanted. The organic layer was washed with water, dried over MgSO₄,filtered and the solvent was evaporated. The crude was purified bypreparative LC on (Irregular SiOH 20-45 μm 450 g Matrex), mobile phase(85% Heptane, 15% AcOEt) to give 4.5 g of intermediate C1 (87% yield).

Overall Scheme in the Preparation of Final Products: Method 2

Synthesis of Intermediate H1

Wilkinson's catalyst (44 mg; 47.5 μmol) was added to a solution of F1(190 mg; 475 μmol) in THF/MeOH (50/50) (50 mL) purged by N₂ bubbling for15 min. The mixture was hydrogenated (8 bars) at rt for 16 h. Themixture was purged for 15 min and Wilkinson's catalyst (44 mg; 47.5μmol) was further added. The reaction mixture was hydrogenated (8 bars)at rt for 4 h. The mixture was concentrated in vacuo to give a brownoil. The oil was purified by preparative LC (Irregular SiOH 15-40 μm, 12g Grace, dry loading, mobile phase gradient: from CH₂Cl₂/EtOAc 100/0 to80/20) to give 150 mg of intermediate H1 as a yellow solid (79% yield).

Synthesis of Final Compound 2

Compound 2 was obtained using the procedure to prepare compound 1 (54mg, 44% yield).

Overall Scheme in the Preparation of Final Products: Method 3

Synthesis of Intermediate J1

I1 (5.9 g; 35.6 mmol) was added to a solution of A1 (7.3 g; 19.8 mmol),K₂CO₃ (5.5 g; 39.6 mmol) and NaI (3.3 g; 21.8 mmol) in acetone (145 mL).The mixture was stirred at rt for 20 h.

The mixture was filtered through a pad of celite and the filtrate wasevaporated in vacuo to give an orange solid. The residue was taken up inCH₂Cl₂. The precipitate was filtered and the filtrate was concentratedin vacuo to give 13 g of a yellow oil. The crude compound was purifiedby preparative LC (Irregular SiOH 15-40 μm, 300 g Interchim, mobilephase gradient: from Heptane/EtOAc 100/0 to 80/20). The fractionscontaining product were combined and the solvent was removed in vacuo togive 7.1 g of intermediate J1 (72% yield) as a yellow oil.

Synthesis of Intermediate K1

In a schlenk flask, a solution of J1 (7.1 g; 14.2 mmol) in THF (130 mL)and an aqueous solution of NH₃ (30%) (130 mL) was stirred at rt for 16h. The mixture was taken up with EtOAc and a saturated water solution ofNaCl, layers were separated. The organic layer was dried over MgSO₄,filtered and concentrated in vacuo to give 6.4 g of a yellow oil (100%yield).

Synthesis of Intermediate L1

NaH (2.2 g; 54.2 mmol) was added portion wise at rt and under N₂atmosphere to 3-buten-1-ol (76 mL). The mixture was stirred at rt for 30min before being added drop wise at 0° C. to a solution of K1 (5.9 g;13.6 mmol) in THF (150 mL). The resulting mixture was stirred at 0° C.for 1 h. The mixture was poured into an aqueous saturated NH₄Clsolution. EtOAc and satured aqueous NaCl solution were added, the layerswere separated. The organic layers was dried over MgSO₄, filtered andconcentrated in vacuo to give a yellow residue which was azeotropicallydistilled with toluene (once) to give 6.6 g of a yellow oil. The crudecompound was purified by preparative LC (Irregular SiOH 15-40 μm, 220 gGrace, mobile phase gradient: from Heptane/EtOAc 100/0 to 50/50). Thefractions containing product were combined and the solvent was removedin vacuo to give 4.46 g of intermediate L1 (77% yield) as a yellow oil.

Synthesis of Intermediate M1

The reaction was performed in 2 batches.

Typical Procedure for One Batch:

A solution of L1 (2.45 g; 5.75 mmol) in dry CH₂Cl₂ (1.7 L) was degassedby N₂ bubbling for 15 min. Grubbs catalyst 2^(nd) generation (488 mg;574 μmol) was added and the mixture was stirred at rt for 72 h.SiliaBond DMT (7.66 g; 4.59 mmol) was added and the mixture was stirredat rt for 16 h. The 2 batches were combined and filtered through celite.The filtrate was concentrated in vacuo to give a black solid. The crudecompound was purified by preparative LC (Irregular SiOH 15-40 μm, 150 gMerck, mobile phase gradient: from Heptane/EtOAc 100/0 to 50/50). Thefractions containing product were combined and the solvent was removedin vacuo to give 230 mg of fraction 1 and 2.3 g of fraction 2. Fraction2 was re-purified by preparative LC (Stationary phase: irregular SiOH 40μm 120 g, mobile phase: Heptane/CH₂Cl₂/MeOH 55/43/2). The isolatedcompound was combined with fraction 1 and purified by achiral SFC(Stationary phase: Chiralpak IC 5 μm 250×20 mm, mobile phase: 70% CO₂,30% iPrOH) to give 1.51 g of intermediate M1 (33% yield, isomer E) as ayellow solid.

Synthesis of Final Compound 3

Iron (631 mg; 11.3 mmol) was added to a solution of M1 (750 mg; 1.88mmol) in AcOH (150 mL) and water (25 mL). The mixture was stirred at 80°C. for 16 h. Iron (315 mg; 5.65 mmol) was added and the mixture wasstirred at 80° C. for 2 h. Iron (315 mg; 5.65 mmol) was added and themixture was stirred at 80° C. for 4 h. Iron (315 mg; 5.65 mmol) wasadded and the mixture was stirred at 80° C. for 16 h. The mixture wasconcentrated until dryness. DMF was added, the mixture was filteredthrough celite and the celite was rinsed with hot DMF. SiliaBondimidazole (48.7 g; 56.5 mmol) was added to the filtrate and the mixturewas stirred at rt for 16 h. The mixture was filtered through celite, thecelite was rinsed with DMF and the filtrate was concentrated in vacuo.The crude compound was purified by preparative LC (irregular SiOH, 15-40μm, 25 g Merck, mobile phase gradient: from CH₂Cl₂/MeOH/NH₃aq 98/2/0.2to 85/15/1.5) to give 2 fractions. Fraction 1 was taken-up with EtOH andfiltered to give fraction 3 and fraction 2 was taken-up with MeCN andfiltered to give fraction 4. Fractions 3 and 4 were combined in EtOH,filtered and dried in vacuo to give 199 mg of final compound 3 (33%yield).

Overall Scheme in the Preparation of Final Products: Method 4

Synthesis of Intermediate N1

Wilkinson's catalyst (46 mg; 50.2 μmol) was added to a solution of M1(200 mg; 502 μmol) in THF/MeOH (50/50) (50 mL) purged by N₂ bubbling for15 min. The mixture was hydrogenated (7 bars) at rt for 20 h. Themixture was purged by N2 bubbling for 15 min, further Wilkinson'scatalyst (46 mg; 50.2 μmol) was added and the reaction mixture washydrogenated (7 bars) at rt for 16 h. The reaction mixture wasconcentrated in vacuo to give a green oil. The oil was purified bypreparative LC (Irregular SiOH 15-40 gum, 25 g Merck, dry loading,mobile phase gradient: from Heptane/EtOAc 100/0 to 70/30) to give 130 mgof intermediate N1 as a yellow solid (66% yield).

Synthesis of Intermediate O1

In a pressure vessel reactor, N1 (110 mg; 275 μmol) was hydrogenated inEtOH (5 mL) with Pd/C (10%) (30 mg; 28.5 μmol) as catalyst at 40° C. (3bars) for 6 h. The catalyst was removed by filtration over celite, thecelite was washed with EtOH and the filtrate was evaporated under vacuumto give 100 mg of a yellow residue (98% yield). Intermediate O1 was usedin the next step without further purification.

Synthesis of Final Compound 4

In a sealed tube, O1 (100 mg; 270 μmol) in pure acetic acid (5 mL) wasstirred at rt for 90 min.

The solvent was removed under reduced pressure to give a yellow residue.The residue was taken up with CH₂Cl₂ and the solvent was removed underreduced pressure (twice) to give 87 mg of a yellow-green solid. Thesolid was azeotropically distilled with toluene (four times), and wasthen triturated and sonicated in Et₂O. The mixture was filtered off(glass frit n° 5) to give 75 mg of final compound 4 (77% yield, acetatesalt).

Overall Scheme in the Preparation of Final Products: Method 5

Synthesis of Intermediate Q1

To a solution of A1 (3.52 g; 9.54 mmol) and K₂CO₃ (2.64 g; 19.1 mmol) inacetone (80 mL) was added P1 (1.93 g; 10.5 mmol) and NaI (1.57 g; 10.5mmol) at rt. The mixture was stirred at rt for 16 h, further P1 (1.5 g;8.17 mmol) was added and the mixture was stirred at rt for 24 h. Thereaction mixture was filtered through a pad of celite and the filtratewas evaporated in vacuo to give a black residue. The residue waspurified by preparative LC (irregular SiOH 15-40 μm, 80 g Grace, dryloading, mobile phase gradient: from Heptane/EtOAc 100/0 to 50/50) togive 3.28 g of intermediate Q1 as an orange oil (67% yield).

Synthesis of Intermediate R1

In a schlenk flask, to a solution of Q1 (3.28 g; 6.36 mmol) in THF (52mL), was added an aqueous solution of NH₃ (30%) (52 mL) at rt. Themixture was stirred at rt for 26 h and further aqueous solution of NH₃(10 mL) was added and the mixture was stirred at rt for 4 h. The mixturewas taken up with EtOAc and saturated aqueous solution of NaCl, thelayers were separated and the organic layer was dried over MgSO₄,filtered and the solvent was removed under reduced pressure to give 2.74g of intermediate R1 as a yellow oil (87% yield).

Synthesis of Intermediate S1

NaH (60% in oil) (888 mg; 22.2 mmol) was added portion wise to3-buten-1-ol (30 mL; 354 mmol) at rt. The mixture was stirred at rt for30 min before being added drop wise to a solution of R1 (2.74 g; 5.63mmol) in THF (62 mL) at 0° C. The resulting mixture was stirred at rtfor 1 h and was poured in NH₄Cl saturated aqueous solution. EtOAc andNaCl saturated aqueous solution were added, the layers were separatedand the aqueous layer was extracted with EtOAc (once). The combinedorganic layers were dried over MgSO₄, filtered and the solvent wasremoved under reduced pressure to give a yellow oil. The oil waspurified by preparative LC (Irregular SiOH 15-40 μm, 80 g Grace, dryloading, mobile phase gradient: from Heptane/EtOAc 100/0 to 20/80) togive 1.06 g of intermediate S1 as a yellow residue (42% yield).

Synthesis of Intermediate T1

The reaction was performed in two batches of 480 mg of intermediate S1.

Herein is reported the procedure for one batch:

In a schlenck flask, a solution of S1 (480 mg; 1.08 mmol) andchlorodicyclohexylborane (1M in hexane) (216 μL; 216 μmol) in drydichloroethane (300 mL) was stirred at 80° C. and under N₂ atmospherefor 1 h. Grubbs-Hoveyda catalyst 2^(nd) generation (68 mg; 108 μmol) wasadded and the mixture was stirred at 120° C. for 2 h.

The two batches were mixed, SiliaBond DMT (2.84 g; 1.73 mmol) was addedand the mixture was stirred at rt for 20 h.

The mixture was filtered through a pad of celite, the celite was washedwith EtOAc and the filtrate was evaporated in vacuo to give a brownsolid. The brown solid was purified by preparative LC (Irregular SiOH15-40 μm, 40 g Grace, dry loading, mobile phase gradient: CH₂Cl₂/EtOAcfrom 100/0 to 20/80) to give 610 mg of a yellow residue (mixture of Eand Z isomers, intermediate U1). 310 mg of intermediate U1 was purifiedby Reverse phase (Stationary phase: Nucleodur-Sphinx rp 5 μm 21×150 mm,mobile phase: Gradient from 70% formic acid 0.1%, 30% MeCN to 0% formicacid 0.1%, 100% MeCN) to give 195 mg of intermediate T1 (E isomer) as ayellow solid (22% yield).

Synthesis of Final Compound 5

A mixture of T1 (160 mg; 385 μmol) and iron (129 mg; 2.31 mmol) inacetic acid (21 mL) and water (2.4 mL) was stirred at 80° C. for 7 h.Further iron (129 mg; 2.31 mmol) was added and the mixture was stirredat 80° C. for 16 h. Further iron (129 mg; 2.31 mmol) was added and themixture was stirred at 80° C. for 3 h. The mixture was concentrated invacuo to give a residue. The residue was diluted in DMF and filteredthrough a pad of celite. SiliaBond imidazole (12.7 g; 14.7 mmol) wasadded to the filtrate and the mixture was stirred at rt for 16 h. Themixture was filtered through a pad of celite and the filtrate wasevaporated in vacuo to give a brown solid. The brown solid was purifiedby preparative LC (irregular SiOH 15-40 μm, 12 g Grace, dry loading,mobile phase gradient: from CH₂Cl₂/MeOH/NH₃aq 97/3/0.3 to 80/20/2) togive 65 mg of an off-white solid. The solid was purified by Reversephase (Stationary phase: X-Bridge-C18 5 μm 30*150 mm, mobile phasegradient: from H₂O (0.5% NH₄CO₃)/MeOH 70/30 to 0/100) to give 43 mg offinal compound 5 as a white solid (31% yield, E isomer).

Overall Scheme in the Preparation of Final Products: Method 6

Synthesis of Intermediate V1

Wilkinson's catalyst (58 mg; 62.6 jμmol) was added to a solution of U1(Z/E mixture, 260 mg; 626 μmol) in THF/MeOH (50/50) (66 mL) purged by N₂bubbling for 15 min. The mixture was hydrogenated (7 bars) at rt for 16h. Further Wilkinson's catalyst (58 mg; 62.6 μmol) was added and themixture was hydrogenated (7 bars) at rt for 6 h. The reaction mixturewas concentrated in vacuo to give a brown solid. The solid was purifiedby preparative LC (Irregular SiOH 15-40 μm, 25 g Merck, dry loading,mobile phase gradient: from Heptane/EtOAc 100/0 to 50/50) to give 250 mgof intermediate V1 as a yellow oil (54% yield).

Synthesis of Final Compound 6

A mixture of V1 (238 mg; 359 μmol) and iron (120 mg; 2.16 mmol) inacetic acid (20 mL) and water (2.2 mL) was stirred at 80° C. for 6 h.Further iron (120 mg; 2.16 mmol) was added and the mixture was stirredat 80° C. for 20 h. Further iron (120 mg; 2.16 mmol) was added and themixture was stirred at 80° C. for 5 h. The mixture was concentrated invacuo to give a residue. The residue was diluted in DMF and filteredthrough a pad of celite. SiliaBond imidazole (11.1 g; 12.9 mmol) wasadded to the filtrate and the mixture was stirred at rt for 16 h. Themixture was filtered through a pad of celite and the filtrate wasevaporated in vacuo to give a brown solid. The solid was purified bypreparative LC (irregular SiOH 15-40 μm, 12 g Grace, dry loading, mobilephase gradient: from CH₂Cl₂/MeOH/NH₃aq 97/3/0.3 to 80/20/2) to give 32mg of an off-white solid. The solid was taken up with water, trituratedand sonicated. The resulting suspension was filtered off (glass frit n°5) and washed with Et₂O (twice) to give 19 mg of final compound 6 as anoff-white solid (15% yield).

Overall Scheme in the Preparation of Final Products: Method 7

Synthesis of Intermediate W1

NaH (60% in oil) (2.1 g; 52.1 mmol) was added portion wise to3-buten-1-ol (74 mL) at rt. The mixture was stirred at rt for 30 minbefore being added drop wise to a solution of D1 (5.97 g; 13.2 mmol) inTHF (150 mL) at 0° C. The resulting mixture was then stirred at rt for 2h 30 min and was poured in aqueous saturated solution of NH₄Cl. EtOAcand saturated aqueous solution of NaCl were added, the layers wereseparated and the aqueous layer was extracted with EtOAc (once). Thecombined organic layers were dried over MgSO₄, filtered and the solventwas removed under reduced pressure to give 6.77 g of a yellow oil. Thecrude was purified by preparative LC (Irregular SiOH 15-40 μm, 120 gGrace, liquid injection, mobile phase gradient: from Heptane/EtOAc 100/0to 50/50) to give 5.12 g of intermediate W1 as a yellow oil (83% yield).

Synthesis of Intermediate X1

To a solution of W1 (3 g; 6.78 mmol) in CH₂Cl₂ (1.3 L) degassed by N₂bubbling for 15 min was added Grubbs catalyst 2^(nd) generation (578 mg;678 μmol) at rt. The solution was stirred at rt for 20 h. SiliaBond DMT(8.89 g; 5.42 mmol) was added and the mixture was stirred at rt for 20h. The reaction mixture was filtered through a pad of celite and thesolvent was removed under reduced pressure to give a brown residue,which was combined with another batch (0.226 mmol scale). The combinedresidue was taken up with MeOH, sonicated and heated to give aprecipitate which was filtered off to give 3.2 g of a brown solid. Thecrude was purified by preparative LC (irregular SiOH, 15-40 μm, 220 ggrace, liquid injection, mobile phase gradient: from CH₂Cl₂/EtOAc 100/0to 50/50) to give 1.7 g of fraction 1 as a pale brown solid. Fraction 1was taken up with MeOH, sonicated and heated to give a precipitate whichwas filtered off to give 820 mg of fraction 2 as a pale brown solid.

The filtrate was concentrated in vacuo to give 590 mg of fraction 3 as abrown residue (impure X1). Fraction 2 was purified by preparative LC(Stationary phase: Spherical bare silica 5 μm 150×30.0 mm, mobile phasegradient: from Heptane/EtOAc 85/15 to 0/100) to give 435 mg ofintermediate X1 as a yellow solid (E isomer, 15% yield).

Fraction 3 was purified with another batch.

Synthesis of Final Compound 10

A mixture of X1 (430 mg; 1.04 mmol) and iron (579 mg; 10.4 mmol) inacetic acid (43 mL) and water (3 mL) was stirred at 50° C. for 4 h. Themixture was concentrated until dryness. DMF was added. The mixture wassonicated, heated and filtered through a pad of celite and the celitewas rinsed with hot DMF. SiliaBond imidazole (17.9 g; 20.8 mmol) wasadded to the filtrate and the mixture was stirred at rt for 16 h. Themixture was filtered through celite, the celite was rinsed with DMF andthe filtrate was concentrated in vacuo to give 670 mg of crude compound.The crude was purified by preparative LC (irregular SiOH, 15-40 μm, 25 gMerck, mobile phase gradient: from CH₂Cl₂/MeOH/NH₃aq 98/2/0.2 to85/15/1.5) to give an off-white solid. The solid was dried at 40° C.under reduced pressure during 20 h to give 295 mg of final compound 10as an off-white solid (84% yield).

Overall Scheme in the Preparation of Final Products: Method 8

Synthesis of Intermediate Y1

Wilkinson's catalyst (103 mg; 111 μmol) was added to a solution of X1(230 mg; 0.555 mmol) in THF/MeOH (50/50) (40 mL) purged by N₂ bubblingfor 15 min. The mixture was hydrogenated (8 bars) at rt for 24 h. Thereaction mixture was concentrated in vacuo to give a brown residue. Thesolid was purified by preparative LC (irregular SiOH, 15-40 μm, 12 gGrace, dry loading, mobile phase gradient: from CH₂Cl₂/EtOAc 100/0 to90/10) to give 55 mg of intermediate Y1 as a yellow residue (24% yield).

Synthesis of Final Compound 14

A mixture of Y1 (55 mg; 0.132 mmol) and iron (74 mg; 1.32 mmol) inacetic acid (5.5 mL) and water (0.4 mL) was stirred at 50° C. for 20 h.More iron (37 mg; 0.66 mmol) was added and the mixture was stirred at50° C. for 3 h. More iron (37 mg; 0.66 mmol) was added and the mixturewas stirred at 50° C. for 20 h. The mixture was filtered through a padof celite and the celite was rinsed with acetic acid. More iron (74 mg;1.32 mmol) was added to the filtrate and the mixture was stirred at 50°C. for 88 h. More iron (74 mg; 1.32 mmol) was added to the filtrate andthe mixture was stirred at 80° C. for 24 h. The cyclisation was notcomplete. The mixture was concentrated in vacuo to give a brown solid.

TiCl₃ (8.60 mL; 10.0 mmol) was added drop wise to a solution of thebrown solid in C (19 mL). The mixture was stirred at rt overnight. Themixture was basified by addition of K₂CO₃ powder at 0° C. The resultingmixture was filtered through a pad of celite and the celite was washedwith a solution of AcOEt/MeOH (8:2). The filtrate was concentrated invacuo. The crude solid was purified by preparative LC (irregular SiOH,15-40 μm, 10 g Merck, dry loading, mobile phase gradient: fromCH₂Cl₂/MeOH/NH₃aq 98/2/0.2 to 85/15/1.5). The fractions containingproduct were combined and the solvent was removed in vacuo to give 20 mgof final compound 14 (12% yield) as an off-white solid.

Overall Scheme in the Preparation of Final Products: Method 9

Synthesis of Intermediate A2

Methanesulfonyl chloride (8.4 mL; 108 mmol) was added to a solution ofZ1 (14 g; 72.1 mmol), NEt₃ (20 mL; 144 mmol) and LiCl (4.6 g; 108 mmol)in dry CH₂Cl₂ (980 mL). The mixture was stirred at rt for 1 h 30. Waterwas added and the layers were separated. The organic layer was washedwith water (once), dried over MgSO₄, filtered and concentrated in vacuoto give 18.8 g of A2 (96%) as a green oil.

Synthesis of Intermediate B2

Intermediate B2 was obtained using the procedure described forintermediate C1 (78% yield as a yellow oil).

Synthesis of Intermediate C2

Intermediate C2 was obtained using the procedure described forintermediate D1 (quantitative yield as a yellow oil).

Synthesis of Intermediate D2

Intermediate D2 was obtained using the procedure described forintermediate W1 (64% yield as a yellow solid).

Synthesis of Intermediate E2

A solution of D2 (1 g; 2.12 mmol) in CH₂Cl₂ (400 mL) was degassed by N₂bubbling for 15 min. Grubbs catalyst 2^(rd) generation (181 mg; 212μmol) was added and the mixture was stirred at rt for 16 h. SiliaBondDMT (2.78 g; 1.69 mmol) was added and the mixture was stirred at rt for16 h. The mixture was filtered through a pad of celite and the filtratewas concentrated in vacuo to give 1.11 g of a brown oil. The crude waspurified by preparative LC (Irregular SiOH 15-40 μm, 50 g Merck, mobilephase gradient: from CH₂Cl₂/EtOAc 100/0 to 90/10). The fractionscontaining product were combined and the solvent was removed in vacuo togive 386 mg of intermediate E2 (41%, isomer E (96.2%)+isomer Z (3.8%))as a yellow foam.

Synthesis of Final Compound 15

Iron (291 mg; 5.21 mmol) was added to a solution of E2 (386 mg; 0.869mmol) in acetic acid (36 mL) and water (3 mL). The mixture was stirredat 80° C. for 6 h. Iron (146 mg; 2.61 mmol) was added and the mixturewas stirred at 80° C. for 16 h. Iron (146 mg; 2.61 mmol) was added againand the mixture was stirred at 80° C. for 5 h. The mixture wasconcentrated until dryness. DMF was added, the mixture was filteredthrough celite and the celite was rinsed with DMF. Siliabond Imidazole(18 g; 20.9 mmol) was added to the filtrate and the mixture was stirredat rt for 72 h. The mixture was filtered through celite, the celite wasrinsed with DMF and the filtrate was concentrated in vacuo to give 428mg of a brown solid. The solid was taken up in CH₃CN leading toprecipitation. The precipitate was filtered to give 267 mg of a brownsolid. The solid was purified by preparative LC (Irregular SiOH 15-40μm, 10 g Merck, dry loading, mobile phase gradient: fromCH₂Cl₂/MeOH/NH₃aq 95/5/0.5 to 85/15/1.5). The fractions containingproduct were combined and the solvent was removed in vacuo to give 124mg of an off-white solid. The solid was purified by Reverse phase(Stationary phase: Sunfire-C18 5 μm 19×150 mm, mobile phase gradient:from CH₃CN/H₂O (formic acid 0.1%) 5/95 to 50/50) to give 72 mg of finalcompound 15 (23% yield) as a white solid.

Overall Scheme in the Preparation of Final Products: Method 10

Synthesis of Intermediate F2

Intermediate F2 was obtained with the procedures described forintermediate F1 (E isomer).

Synthesis of Final Compound 16

At rt, TiCl₃ (12.3 mL; 14.341 mmol) was added drop wise to a mixture ofF2 (300 mg; 0.717 mmol) in THF (30 mL). The mixture was stirred at rtfor 2 hours. The mixture was cooled down to 0° C. and basified withK₂CO₃ powder. The resulting muddy mixture was filtered through a pad ofcelite and the celite was washed with a solution of AcOEt/CH₃OH 8/2. Thefiltrate was partially evaporated to give 175 mg of final compound 16after filtration of a white solid and drying under vacuum pressure at85° C. (71% yield).

Synthesis of Final Compound 17

The hydrochloride salt was prepared with 10 eq of HCl 4N in dioxane,which was added to the suspension of compound 16 (100 mg; 0.292 mmol) inCH₃OH (10 mL). The precipitate was stirred for 3 h, filtered and driedunder vacuum at 90° C. overnight. The solid was solubilized inMeOH/CH₂Cl₂ 50/50, CH₃CN was added and the solvent was evaporated up toprecipitation of a white solid, which was filtered and dried undervacuum at 90° C. to give 47 mg of final compound 17 as an HCl salt (0.93HCl, 0.51 H₂O; 42% yield).

Overall Scheme in the Preparation of Final Products: Method 11

Synthesis of Intermediate H2

At −20° C. under a N₂ flow, G2 (22.0 g; 72.04 mol) in THF (100 mL) wasadded drop wise to a suspension of LiAlH₄ (3.28 g; 86.45 mmol) in THF(120 mL). The mixture was stirred at 0° C. for 1 h. 3.5 mL of water wasadded dropwise, followed by 3.5 mL of NaOH 3N and 10 mL of water. Theresulting mixture was filtered through a pad of celite and the celitewas washed with EtOAc. The filtrate was concentrated under reducedpressure to give 19 g of intermediate H2 as a yellow oil (quantitativeyield).

Synthesis of Intermediate 12

At 0° C., diisopropylazodicarboxylate (4.0 mL; 20.32 mmol) was addeddrop wise to a mixture of A1 (5.0 g; 13.55 mmol), H2 (4.28 g; 16.26mmol) and PPh₃ (5.33 g; 20.327 mmol) in THF (100 mL). The mixture wasstirred at rt for 12 h. EtOAc and water were added. The layers weredecanted. The organic layer was washed with water, dried over MgSO₄,filtered and the solvent was evaporated. The crude compound wasdissolved in Heptane/EtOAc 80/20, the precipitate was filtered off(mainly POPh3) and the filtrate was purified by chromatography.Purification was carried out by flash chromatography over silica gel(15-40 μm, 220 g, Heptane/EtOAc 80/20) The pure fractions were collectedand evaporated to dryness to give 8.2 g of intermediate I2 (99% yield.

Synthesis of Intermediate J2

I2 (8.2 g; 13.349 mmol) was stirred in NH₄OH (100 mL) and THF (100 mL)at rt for 24 h. The mixture was half evaporated under reduced pressure.The residue was taken up with EtOAc. The organic layer was washed withwater, dried over MgSO₄, filtered and the solvent was evaporated to give8.15 g of intermediate J2 (quantitative yield). The crude compound wasused directly in the next reaction step.

Synthesis of Intermediate K2

Under a N₂ flow, NaH (60% in oil) (1.15 g; 28.64 mmol) was added portionwise to allyl alcohol (35 mL) at rt. The mixture was stirred at rt for30 min before being added drop wise to a solution of J2 (4.0 g; 7.26mmol) in THF (80 mL) at 0° C. The resulting mixture was then stirred atrt for 2 h 30 min and was poured in a saturated solution of NH₄Cl. EtOAcand a saturated aqueous solution of NaCl were added, the layers wereseparated and the aqueous layer was extracted with EtOAc (once). Thecombined organic layers were dried over MgSO₄, filtered and the solventwas removed under reduced pressure to give 4.7 g of a yellow oil.Purification was carried out by flash chromatography over silica gel(15-40 μm, 80 g, CH₂Cl₂/Heptane 65/35). The pure fractions werecollected and evaporated to dryness to give 2.65 g of intermediate K2(69% yield).

Synthesis of Intermediate L2

Prior to the reaction, the dichloroethane was degassed by bubbling N₂through.

In a Slenck tube, a solution of K2 (1.3 g; 2.464 mmol) andchlorodicyclohexylborane (1 M in hexane) (493 μL; 0.493 mmol) indichloroethane (600 mL) was stirred at 80° C. under N₂ for 1 h.Grubbs-Hoveyda catalyst 2^(nd) generation (609 mg; 0.493 mmol) was addedand the mixture was stirred at 120° C. for 16 h. Siliabond DMT (2.98 g;1.82 mmol) was added and the mixture was stirred at rt for 16 h. Thereaction mixture was filtered through celite and the filtrate wasevaporated in vacuo to give 1.6 g which was combined with anotherreaction (2.46 mmol scale) before purification (total weight to purify3.2 g). Purification was carried out by flash chromatography over silicagel (15-40 μm, 80 g, CH₂Cl₂/CH₃OH: 99.5/0.5). The pure fractions werecollected and evaporated to dryness to give 0.99 g of F1 (E/Z mixture ofexpected compound, 40% yield) and 0.65 g of F2 (starting material K2).

F1 was further purified by achiral SFC (Stationary phase: NH₂ 5 μm150*30 mm), Mobile phase: 92% CO₂, 8% MeOH) to give 664 mg ofintermediate L2 (E isomer, 27% yield).

Synthesis of Intermediate M2

Iron (1.45 g; 26.025 mmol) was added to a mixture of L2 (0.65 g; 1.301mmol) in acetic acid (15 mL) and water (1.5 mL). The mixture was stirredat 50° C. for 3 h, and then filtered through celite with CH₂Cl₂/MeOH.The filtrate was concentrated under reduced pressure. The compound waspurified by flash chromatography over silica gel column (15-40 μm; 80 g,eluent CH₂Cl₂/CH₃OH/NH₄OH 96/4/0.5) to give 640 mg. A secondpurification was carried out by flash chromatography over silica gel(15-40 μm, 40 g, CH₂Cl₂/CH₃OH/NH₄OH: 97/3/0.2). The pure fractions werecollected and evaporated to dryness to give 240 mg of intermediate M2(38% yield).

Synthesis of Final Compound 18

At 0° C., CF₃CO₂H (0.455 mL) was added drop wise to a mixture of M2 (100mg, 0.236 mmol) in CH₂Cl₂ (1 mL). The mixture was stirred at rtovernight, and then basified with a 10% solution of K₂CO₃ in water. Theprecipitate was filtered off, washed with water and CH₃CN, and finallydried under vacuum to afford 35 mg of final compound 18 (E isomer, 46%yield).

Overall Scheme in the Preparation of Final Products: Method 12

Synthesis of Intermediate N2

A mixture of M2 (140 mg, 0.331 mmol) in THF/CH₃OH (50/50) (30 mL) washydrogenated under a 10 Bars pressure with Wilkinson's catalyst (61.2mg, 0.0661 mmol) for 72 h. Siliabond DMT (441 mg, 0.264 mmol) was addedand the mixture was stirred at rt for 18 h. The mixture was filteredthrough a pad of celite and the celite was washed with CH₂Cl₂/CH₃OH95/5. The filtrate was concentrated under reduced pressure. Purificationwas carried out by flash chromatography over silica gel (15-40 μm, 10 g,CH₂Cl₂/CH₃OH/NH₄OH: 97/3/0.1). The pure fractions were collected andevaporated to dryness to give 62 mg of intermediate N2 (44% yield) usedas such in the next step.

Synthesis of Final Compound 23

At 0° C., CF₃CO₂H (0.281 mL, 3.643 mmol) was added drop wise to amixture of N2 (62 mg, 0.146 mmol) in CH₂Cl₂ (1 mL). The mixture wasstirred at rt overnight. The mixture was basified with a 10% solution ofK₂CO₃ in water. The mixture was extracted twice with CH₂Cl₂ and CH₃OH(80/20). The organic layer was dried over MgSO₄, filtered and thesolvent was evaporated. The crude compound was taken up with DMF, 2 g ofSiO₂ 60-200 μm was added and the resulting suspension was evaporateduntil dryness. This residue was put on the top of a chromatographycolumn (solid deposit). Purification was carried out by flashchromatography over silica gel (15-40 μm, 25 g, CH₂Cl₂/CH₃OH/NH₄OH:95/5/0.5). The pure fractions were collected and evaporated to drynessto give 20 mg. The fraction was taken up with CH₃CN, the precipitate wasfiltered off and dried under vacuum to afford 18 mg of final compound 23(38% yield).

Overall Scheme in the Preparation of Final Products: Method 13

Synthesis of Intermediate O2

Intermediate O2 was obtained with the procedures described forintermediate X1 (E isomer).

Synthesis of Final Compound 21

At rt, TiCl₃ (51.5 mL; 60.128 mmol) was added drop wise to a mixture ofO2 (1.3 g; 3.006 mmol) in THF (130 mL). The mixture was stirred at rtfor 2 h. The mixture was cooled down to 0° C. and then basified withK₂CO₃ powder. The resulting muddy mixture was filtered through a pad ofcelite and the celite was washed with a solution of AcOEt/CH₃OH 8/2. Thefiltrate was partially evaporated to give 380 mg of final compound 21(35% yield) after filtration of a white solid and drying under vacuum at85° C.

Synthesis of Final Compound 22

Compound 21 (118 mg, 0.331 mmol) in CH₃OH (2 mL)+CH₃CN (2 mL) was cooleddown to 10° C. HCl (6M in isopropanol) (0.16 mL, 0.993 mmol) was addeddrop wise and the mixture was stirred at rt for 1 h. The precipitate wasfiltered off, washed with Et₂O and dried under vacuum to give 109 mg offinal compound 22 as an HCl salt (0.76 HCl 0.81 H₂O, 83% yield).

Overall Scheme in the Preparation of Final Products: Method 14

Synthesis of Intermediate P2

A mixture of O2 (320 mg; 0.74 mmol), Wilkinson's catalyst (137 mg; 0.148mmol) in THF/CH₃OH (50/50) (45 mL) was hydrogenated under 10 barspressure at rt for 20 h. Solvent was evaporated under vacuum. The crudecompound was purified by flash chromatography over silica gel column(15-40 μm; 24 g) in Heptane/AcOEt 80/20 to give 310 mg of intermediateP2 (96% yield).

Synthesis of Final Compound 19

At rt, TiCl₃ (9.5 mL; 11.049 mmol) was added drop wise to a mixture ofP2 (0.24 g; 0.552 mmol) in THF (25 mL). The mixture was stirred at rtfor 2 h. The mixture was cooled down to 0° C. and then basified withK₂CO₃ powder. The resulting muddy mixture was filtered through a pad ofcelite and the celite was washed with a solution of AcOEt/CH₃OH 8/2. Thefiltrate was partially evaporated to give 100 mg of final compound 19(50% yield) after filtration of a white solid and drying under vacuum at85° C.

Synthesis of Final Compound 20

Compound 19 (58 mg; 0.162 mmol) in CH₃OH (2 mL)+CH₃CN (4 mL) was cooleddown to 5° C. HCl (6M in isopropanol) (81 μL; 0.486 mmol) was added dropwise and the mixture was stirred at rt for 1 h. The precipitate wasfiltered off, washed with diisopropylether and dried under vacuum at 90°C. to give 57 mg of final compound 20 as an HCl salt (0.88 HCl 0.04 H₂O,89% yield).

Overall Scheme in the Preparation of Final Products: Method 15

Synthesis of Intermediate R2

At 0° C., diisopropylazodicarboxylate (3.8 mL; 19.107 mmol) was addeddrop wise to a mixture of A1 (4.7 g; 12.738 mmol), Q2 (2.27 g; 12.738mmol) and PPh₃ (5 g; 19.107 mmol) in THF (100 mL). The mixture wasstirred at rt for 12 h. EtOAc and water were added. The layers weredecanted. The organic layer was washed with water, dried over MgSO₄,filtered and the solvent was evaporated. The crude compound was purifiedby column chromatography over silicagel (15-40 μm; 220 g) inHeptane/AcOEt 85/15 to 5.3 g of intermediate R2 (79% yield).

Synthesis of Intermediate S2

R2 (5.3 g; 10.015 mmol) was stirred in THF (80 mL) and NH₄OH (80 mL) atrt for 24 h. The mixture was concentrated under reduced pressure. Theresidue was taken up with CH₂Cl₂, the precipitate (mineral) was filteredoff and the filtrate was concentrated under reduced pressure. The crudecompound was purified by column chromatography over silica gel (15-40μm; 220 g) in Heptane/AcOEt 85/15 to give 3.65 g of intermediate S2 (78%yield).

Synthesis of Intermediate T2

NaH (1.35 g; 33.88 mmol) was added portion wise to allyl alcohol (41 mL)at rt. The mixture was stirred at rt for 30 min before being added dropwise to a solution of S2 (4 g; 8.597 mmol) in THF (100 mL) at 0° C. Theresulting mixture was then stirred at rt for 2 h 30 min and was pouredin an saturated aqueous solution of NH₄Cl. EtOAc and a saturated aqueoussolution of NaCl were added, the layers were separated and the aqueouslayer was extracted with EtOAc (once). The combined organic layers weredried over MgSO₄, filtered and the solvent was removed under reducedpressure to give a yellow oil. The crude compound was purified bypreparative LC (Irregular SiOH 15-40 μm, 120 g Grace, liquid injection,mobile phase gradient: Heptane/EtOAc 85/15) to give 3.2 g ofintermediate T2 as a yellow oil (84% yield).

Synthesis of Intermediate U2

A solution of T2 (1 g; 2.26 mmol) and chlorodicyclohexylborane (1M inhexane) (904 μL; 904.013 μmol) in dry dichloroethane (540 mL) wasstirred at 80° C. and under N₂ atmosphere for 1 h. The mixture wasdegassed by N2 bubbling for 15 min, Grubbs-Hoveyda catalyst 2^(nd)generation (141.6 mg; 226 μmol) was added, the mixture was degassedagain by N₂ bubbling for 15 min and then stirred at 120° C. for 16 h.0.25 eq of catalyst were added again and mixture was stirred at 120° C.for 16 h. Siliabond DMT (5.9 g; 3.616 mmol) was added and the mixturewas stirred rt for 16 h. The mixture was filtered through a pad ofcelite and the filtrate was concentrated under vacuum to give a blackoil. The crude compound was purified by preparative LC (Irregular SiOH15-40 μm, 80 g Merck, mobile phase: CH₂Cl₂/AcOEt 97/3). The fractionscontaining product were combined and the solvent was removed undervacuum to give 335 mg of intermediate U2 (E isomer, 36% yield).

Synthesis of Final Compound 25

Iron (0.45 g; 8.084 mmol) was added to a mixture of U2 (0.335 g; 0.808mmol) in acetic acid (24 mL)+water (5 mL). The mixture was stirredvigorously at 50° C. for 5 h.

CH₂Cl₂ was added and the reaction mixture was filtered through a pad ofcelite, and then washed with acetic acid. The solvent was removed underreduced pressure. The crude was purified by chromatography oversilicagel column (SiO₂ 15-40 μm, 25 g) in CH₂Cl₂/CH₃OH/NH₄OH 96/4/0.5 togive 154 mg of final compound 25 (56% yield). The compound wascrystallized in CH₃OH, filtered and dried under vacuum at 90° C. to give70 mg (25% yield).

Overall Scheme in the Preparation of Final Products: Method 16

Synthesis of Intermediate V2

Intermediate V2 was synthesized using the procedure described forintermediate K2 with 3-butenol as starting material (3.9 g, 44% yield).

Synthesis of Intermediates W2 and X2

Grubbs catalyst 2^(nd) generation (236 mg, 0.277 mmol) was added to amixture of V2 (1.5 g, 2.77 mmol) in dry CH₂Cl₂ (400 mL). The mixture wasstirred at rt under a N₂ flow for 24 h. Siliabond DMT (3.6 g, 2.216mmol) was added and the mixture was stirred at rt for 12 h. The mixturewas filtered through celite, the celite was washed with CH₂Cl₂ and thefiltrate was evaporated. Purification was carried out by flashchromatography over silica gel (15-40 μm, 80 g, CH₂Cl₂/CH₃OH: 99.5/0.5)pure fractions were collected and evaporated to dryness to give 0.98 gof a mixture of W2 and X2. The two isomers were separated by achiral SFC(Stationary phase: CHIRALPAK IC 5 μm 250×20 mm), Mobile phase: 70% CO₂,30% CH₃OH) to give 0.805 g of intermediate W2 (E isomer, 57% yield) and0.14 g of intermediate X2 (Z isomer, 10% yield).

Synthesis of Final Compound 26

Final compound 26 was synthesized with the procedures described forfinal compound 18 (1^(st) step: Y2, 0.68 g, 99% yield; 2^(nd) step: 52mg, 27% yield).

Synthesis of Final Compound 29

Final compound 29 was synthesized with the procedures described forfinal compound 18 (1^(st) step: Z2, 0.12 g, 100% yield; 2^(nd) step: 8mg, 9% yield).

Overall Scheme in the Preparation of Final Products: Method 17

Synthesis of Intermediate B3

Allyl bromide (13 mL, 0.15 mmol) was added drop wise to a mixture of A3(23 g, 0.135 mmol) and K₂CO₃ (28 g, 0.2 mmol) in CH₃CN (460 mL). Themixture was stirred at reflux for 4 h, and then concentrated underreduced pressure. The residue was taken up with water and was extractedwith EtOAc. The organic layers were combined, washed with water, driedover MgSO₄, filtered and the solvent was evaporated. The crude compound(27 g, 95% yield) was used directly in the next reaction step.

Synthesis of Intermediate C3

Under N₂, DIBAL-H (1.2 M in toluene) (97 mL; 116.5 mmol) was added to asolution of B3 (9.8 g; 46.6 mmol) in dry CH₂Cl₂ (250 mL) at 0° C. Thereaction mixture was stirred at 0° C. for 1 h, and then 1 h at rt. Waterwas added. The organic layer was separated from the aqueous layer, driedover MgSO₄, filtered and concentrated under vacuum to give 8.4 g ofintermediate C3 (99% yield). The crude compound was used directly in thenext reaction step.

Synthesis of Intermediate D3

Intermediate D3 was synthesized using the procedure described forintermediate R2 with C3 as starting material (1.9 g, 88% yield).

Synthesis of Intermediate E3

Intermediate E3 was synthesized using the procedure described forintermediate S2 with D3 as starting material (1.8 g, 93% yield).

Synthesis of Intermediate F3

Intermediate F3 was synthesized using the procedure described forintermediate W1 with E3 as starting material (0.65 g, 66% yield).

Synthesis of Intermediate G3

Intermediate G3 was synthesized using the procedure described forintermediate X1 with intermediate F3 as starting material (E isomer, 520mg, 19% yield).

Synthesis of Final Compound 27

Final compound 27 was synthesized using the procedure described forfinal compound 10 with intermediate G3 as starting material (174 mg, 42%yield).

Synthesis of Final Compound 28

Final compound 28 was synthesized using the procedure described forfinal compound 20 with compound 27 as starting material (1.01 HCl 0.89H₂O, 95 mg, 69% yield).

Overall Scheme in the Preparation of Final Products: Method 18

Synthesis of Intermediate H3

A mixture of G3 (600 mg, 1.39 mmol), Wilkinson's catalyst (257 mg; 0.278mmol) in THF/CH₃OH (50/50) (120 mL) was hydrogenated under 12 barspressure at rt for 20 h. The solution was concentrated under reducedpressure. Purification was carried out by flash chromatography oversilica gel (15-40 μm, 30 g, CH₂Cl₂/CH₃OH: 99.5/0.5). The pure fractionswere collected and evaporated to dryness, and then crystallized fromCH₃CN to give 150 mg of intermediate H3 (25% yield).

Synthesis of Final Compound 32

A mixture of H3 (150 mg; 0.345 mmol) and iron (190 mg; 3.45 mmol) inacetic acid (13 mL) and water (1.5 mL) was stirred at 50° C. for 5 h.CH₂Cl₂ was added and the reaction mixture was filtered through a pad ofcelite and concentrated under vacuum. The crude compound was taken upwith DMF, filtered through a pad of celite and concentrated. The solidwas pre-purified by chromatography over silicagel column (SiO₂ 63-200μm. 80 g) in CH₂Cl₂/CH₃OH/NH₄OH (98/2/0.1 to 90/10/0.5). A secondpurification by achiral SFC (Stationary phase: Whelk O1 (S,S) 5 μm250*21.1 mm), Mobile phase: 60% CO₂, 40% CH₃OH (0.3% iPrNH₂)) afforded27 mg of final compound 32 (22% yield).

Overall Scheme in the Preparation of Final Products: Method 19

Synthesis of Intermediate I3

Intermediate 13 was synthesized using the procedure described forintermediate T2 (4.2 g, 83%).

Synthesis of Intermediate J3

Intermediate J3 was synthesized using the procedure described forintermediate F1 (isomer E, 125 mg, 17%).

Synthesis of Final Compound 30

Final compound 30 was synthesized using the procedure described forfinal compound 21 (72 mg, 44% yield).

Synthesis of Final Compound 31

Final compound 31 was synthesized using the procedure described forfinal compound 22 (0.98 HCl 0.15 H₂O, 72 mg, 59% yield).

Overall Scheme in the Preparation of Final Products: Method 20

Synthesis of Intermediate L3

Allyl bromide (1.7 mL; 19.6 mmol) was added to a solution of K3 (3 g;17.8 mmol) and K₂CO₃ (2.7 g; 19.6 mmol) in CH₃CN (90 ml). The mixturewas stirred at 90° C. for 20 h, and then filtered. The filtrate wasconcentrated under vacuum. The crude product was taken up with CH₂Cl₂and an aqueous solution of NaOH 5%. The layers were separated and theorganic layer was dried over MgSO₄, filtered and the solvent was removedunder reduced pressure to give 3.9 g of intermediate L3 (quantitativeyield). The crude compound was used directly in the next reaction step.

Synthesis of Intermediate M3

At 0° C., diisopropylazodicarboxylate (4.8 mL; 24.36 mmol) was addeddrop wise to a mixture of A1 (6 g; 16.2 mmol), L3 (3.2 g; 15.36 mmol)and PPh₃ (6.4 g; 24.36 mmol) in THF (120 mL). The mixture was stirred atrt for 12 h. EtOAc and water were added. The layers were decanted. Theorganic layer was washed with water, dried over MgSO₄, filtered and thesolvent was evaporated. 20 mL of Heptane/AcOEt 70/30 were added toprecipitate a large part of the formed PPh₃O, which was removed byfiltration. The crude product was purified by preparative LC (IrregularSiOH 15-40 μm, 120 g Interchim, mobile phase Heptane/EtOAc 80/20) togive 8 g of intermediate M3 (88% yield)

Synthesis of Intermediate N3

M3 (8.8 g; 15.7 mmol) was stirred in THF (120 mL) and NH₄OH (120 mL) atrt for 24 h. The mixture was concentrated under reduced pressure. Theresidue was taken up with CH₂Cl₂, the precipitate (mineral) was filteredoff and the filtrate was dried over MgSO₄, filtered through a pad ofcelite and concentrated under vacuum. The crude product was purified bypreparative LC (Irregular SiOH 15-40 μm, 120 g Interchim, mobile phaseHeptane/EtOAc 80/20) to afford 3 g of intermediate N3 (38% yield).

Synthesis of intermediate O3

NaH (60% in oil) (0.93 g; 23 mmol) was added portion wise to allylalcohol (28 mL) at rt. The mixture was stirred at rt for 30 min beforebeing added drop wise to a solution of N₃ (2.9 g; 5.85 mmol) in THF (70mL) at 0° C. The resulting mixture was then stirred at rt for 2 h 30 minand was poured into a saturated aqueous solution of NH₄Cl. EtOAc and asaturated aqueous solution of NaCl were added, the layers were separatedand the aqueous layer was extracted with EtOAc (once). The combinedorganic layers were dried over MgSO₄, filtered and the solvent wasremoved under reduced pressure to give a yellow oil. The crude productwas purified by preparative LC (Irregular SiOH 15-40 unm, 120 g Grace,liquid injection, mobile phase heptane/EtOAc 80/20) to give 2.4 g ofintermediate O3 (87% yield).

Synthesis of Intermediate P3

The reaction was carried out on three batches.

A solution of O3 (0.8 g; 1.7 mmol) and chlorodicyclohexylborane (1M inhexane) (0.68 mL; 0.68 mmol) in dry dichloroethane (400 mL) was stirredat 80° C. and under N₂ atmosphere for 1 h. The mixture was degassed byN₂ bubbling for 15 min, Grubbs-Hoveyda catalyst 2^(nd) generation (110mg; 0.17 mol) was added, the mixture was degassed again by N₂ bubblingfor 15 min and then stirred at 120° C. for 16 h. 0.050 eq of catalyst(49 mg, 0.084 mmol) were added and mixture was stirred at 120° C. for 7h. Siliabond DMT (3.3 g; 2.03 mmol) was added and the mixture wasstirred rt for 16 h. The mixture was filtered through a pad of celiteand the filtrate was concentrated under vacuum to give a black oil. Thecrude product was purified by preparative LC (Irregular SiOH 15-40 μm,80 g Interchim, mobile phase Heptane/EtOAc 65/35) to give 190 mg ofintermediate P3 (isomer E, 25% yield).

Synthesis of Final Compound 36

At rt, TiCl₃ (19.3 mL; 22.5 mmol) was added drop wise to a mixture of P3(500 mg; 1.125 mmol) in THF (90 mL). The mixture was stirred at rt for 2h. At 0° C., the mixture was basified with K₂CO₃ powder. The resultingmuddy mixture was filtered through a pad of celite and celite was washedwith a solution of CH₂Cl₂/CH₃OH (90/10). The filtrate was concentratedunder reduced pressure. The residue was taken up in MeOH. The whitesolid was filtered off and dried under vacuum. The product was purifiedby preparative LC (Irregular SiOH 15-40 mrn, 40 g Interchim, mobilephase CH₂Cl₂/CH₃OH/NH₄OH 98/2/0.1) to give 140 mg of final compound 36(34% yield).

LCMS Methods:

General Procedure VDR2 (for Methods V300xV30xx.olp)

The LC measurement was performed using a UPLC (Ultra Performance LiquidChromatography) Acquity (Waters) system comprising a binary pump withdegasser, an autosampler, a diode-array detector (DAD) and a column asspecified in the respective methods below, the column is hold at atemperature of 40° C. Flow from the column was brought to a MS detector.The MS detector was configured with an electrospray ionization source.The capillary needle voltage was 3 kV and the source temperature wasmaintained at 130° C. on the Quattro (triple quadrupole massspectrometer from Waters). Nitrogen was used as the nebulizer gas. Dataacquisition was performed with a Waters-Micromass MassLynx-Openlynx datasystem.

Method V3018V3001

In addition to the general procedure VDR2: Reversed phase UPLC wascarried out on a Waters Acquity BEH (bridged ethylsiloxane/silicahybrid) C18 column (1.7 μm, 2.1×100 mm) with a flow rate of 0.343ml/min. Two mobile phases (mobile phase A: 95% 7 mM ammonium acetate/5%acetonitrile; mobile phase B: 100% acetonitrile) were employed to run agradient condition from 84.2% A and 15.8% B (hold for 0.49 minutes) to10.5% A and 89.5% B in 2.18 minutes, hold for 1.94 min and back to theinitial conditions in 0.73 min, hold for 0.73 minutes. An injectionvolume of 2 μl was used. Cone voltage was 20V for positive and negativeionization mode. Mass spectra were acquired by scanning from 100 to 1000in 0.2 seconds using an interscan delay of 0.1 seconds.

TABLE 1 Compounds of formula (I). Mass LCMS Ret Exact Found Time,Synthesis # STRUCTURE Mass [M + H] Method method NMR  1

324.1 325 1.96, V3018V3001 Method  1 ¹H NMR (500 MHz, DMSO-d₆) δ 10.06(s, 1H), 7.36 (s, 1H), 7.20 (t, J = 7.9 Hz, 1H), 6.76-6.93 (m, 2H), 6.05(s, 1H), 5.94 (dt, J = 6.0, 16.1 Hz, 1H), 5.43- 5.64 (m, 3H), 4.84 (s,2H), 4.40-4.66 (m, 4H)  2

326.1 327 2.02, V3018V3001 Method  2 ¹H NMR (400 MHz, DMSO-d₆) δ 10.04(br. s., 1H), 7.49 (s, 1H), 7.17 (t, J = 7.9 Hz, 1H), 6.69-6.83 (m, 2H),6.15 (s, 1H), 5.54 (s, 2H), 4.89 (s, 2H), 4.28 (t, J = 6.3 Hz, 2H), 4.14(t, J = 6.6 Hz, 2H), 1.34-1.62 (m, 4H)  3

322.1 323 2.3,  V3018V3001 Method  3 ¹H NMR (500 MHz, DMSO-d₆) δ 10.11(br. s., 1H), 7.22 (t, J = 7.6 Hz, 1H), 7.12 (br. s., 1H), 7.09 (d, J =7.6 Hz, 1H), 7.05 (d, J = 7.6 Hz, 1H), 5.74 (s, 1H), 5.51-5.63 (m, 3H),5.03 (td, J = 7.2, 14.9 Hz, 1H), 4.93 (s, 2H), 4.15- 4.26 (m, 2H),3.15-3.23 (m, 2H), 2.24-2.33 (m, 2H)  4

324.2 325 2.36, V3018V3001 Method  4 ¹H NMR (500 MHz, DMSO-d₆) δ 10.20(br. s., 1H), 7.34 (s, 1H), 7.21 (t, J = 7.3 Hz, 1H), 7.06 (d, J = 7.3Hz, 1H), 6.97 (d, J = 7.3 Hz, 1H), 5.59 (s, 2H), 4.93 (s, 2H), 3.91-4.03(m, 2H), 2.55-2.62 (m, 2H), 1.59- 1.71 (m, 2H), 1.12-1.27 (m, 4H)  5

339.1 340 1.85, V3018V3001 Method  5 ¹H NMR (400 MHz, DMSO-d₆) δ 9.91(br. s., 1H), 8.05 (d, J = 4.6 Hz, 1H), 7.38 (d, J = 8.6 Hz, 1H), 7.27(dd, J = 4.6, 8.6 Hz, 1H), 6.20 (s, 1H), 5.82 (dt, J = 7.0, 15.6 Hz,1H), 5.68 (dt, J = 7.1, 15.6 Hz, 1H), 5.46 (s, 2H), 4.91 (s, 2H), 4.33(d, J = 7.1 Hz, 2H), 4.12-4.27 (m, 2H), 2.36-2.46 (m, 2H)  6

341.1 342 1.85, V3018V3001 Method  6 ¹H NMR (400 MHz, DMSO-d₆) δ 9.92(s, 1H), 8.09 (d, J = 4.0 Hz, 1H), 7.43 (d, J = 8.1 Hz, 1H), 7.30 (dd, J= 4.0, 8.1 Hz, 1H), 6.40 (s, 1H), 5.51 (s, 2H), 4.96 (s, 2H), 4.15 (t, J= 6.1 Hz, 2H), 3.97-4.10 (m, 2H), 1.81-1.91 (m, 2H), 1.68-1.78 (m, 2H),1.52-1.65 (m, 2H)  7

354.1 355 1.84, V3018V3001 Method  1 ¹H NMR (400 MHz, DMSO-d₆) δ 10.03(br. s., 1H), 7.36 (d, J = 2.0 Hz, 1H), 6.91 (d, J = 8.1 Hz, 1H), 6.80(dd, J = 2.0, 8.1 Hz, 1H), 6.06 (dt, J = 6.0, 16.2 Hz, 1H), 5.93 (s,1H), 5.54 (s, 2H), 5.41 (dt, J = 5.6, 16.2 Hz, 1H), 4.78 (s, 2H),4.50-4.67 (m, 2H), 4.28-4.48 (m, 2H), 3.71 (s, 3H)  8

356.1 357 1.86, V3018V3001 Method  2 ¹H NMR (400 MHz, DMSO-d₆) δ 10.03(br. s., 1H), 7.54 (br. s., 1H), 6.87 (d, J = 8.1 Hz, 1H), 6.76 (d, J =8.1 Hz, 1H), 6.24 (br. s., 1H), 5.53 (br. s., 2H), 4.82 (br. s., 2H),4.19-4.32 (m, 2H), 4.01-4.16 (m, 2H), 3.68 (br. s., 3H), 1.34-1.60 (m,4H)  9

323.2 324 2.36, V3018V3001 Method  1 Method  2 ¹H NMR (400 MHz, DMSO-d₆)δ 9.73 (s, 1H), 7.57 (s, 1H), 7.16 (t, J = 7.6 Hz, 1H), 7.02 (d, J = 7.6Hz, 1H), 6.89 (d, J = 7.6 Hz, 1H), 5.33 (t, J = 6.6 Hz, 1H), 5.25 (s,1H), 5.15 (s, 2H), 4.85 (s, 2H), 2.91 (q, J = 6.6 Hz, 2H), 2.58-2.72 (m,2H), 1.59-1.85 (m, 2H), 0.96-1.21 (m, 4H) 10

338.1 339 2.22, V3018V3001 Method 7 ¹H NMR (400 MHz, DMSO-d₆) δ 10.05(br. s., 1H), 7.20 (t, J = 7.8 Hz, 1H), 6.92 (d, J = 7.8 Hz, 1H), 6.89(s, 1H), 6.77 (d, J = 7.8 Hz, 1H), 6.12 (s, 1H), 5.50-5.64 (m, 3H), 5.35(dt, J = 4.5, 16.2 Hz, 1H), 4.87 (s, 2H), 4.58 (d, J = 4.5 Hz, 2H), 4.24(t, J = 5.1 Hz, 2H), 2.21-2.32 (m, 2H) 11

352.2 353 2.33, V3018V3001 Method  1 ¹H NMR (500 MHz, DMSO-d₆) δ 10.07(s, 1H), 7.32 (s, 1H), 7.18 (t, J = 7.7 Hz, 1H), 6.82 (d, J = 7.7 Hz,1H), 6.79 (dd, J = 1.7, 7.7 Hz, 1H), 5.98 (dt, J = 7.7, 15.5 Hz, 1H),5.80 (s, 1H), 5.56 (s, 2H), 5.51 (td, J = 5.8, 15.5 Hz, 1H), 4.84 (s,2H), 4.71 (d, J = 5.8 Hz, 2H), 3.96 (t, J = 7.7 Hz, 2H), 1.92-2.07 (m,2H), 1.49-1.64 (m, 2H) 12

354.1 355 2.04, V3018V3001 Method  1 ¹H NMR (400 MHz, DMSO-d₆) δ 10.05(br. s., 1H), 6.94 (s, 1H), 6.47 (s, 1H), 6.39 (s, 1H), 6.05 (s, 1H),5.87 (dt, J = 6.0, 15.7 Hz, 1H), 5.45-5.68 (m, 3H), 4.79 (s, 2H), 4.41-4.61 (m, 4H), 3.64 (s, 3H) 13

356.1 357 2.1,  V3018V3001 Method  2 ¹H NMR (500 MHz, DMSO-d₆) δ 10.05(s, 1H), 7.08 (s, 1H), 6.24-6.44 (m, 2H), 6.16 (s, 1H), 5.55 (s, 2H),4.84 (s, 2H), 4.25 (t, J = 6.3 Hz, 2H), 4.13 (t, J = 6.8 Hz, 2H), 3.64(s, 3H), 1.47-1.62 (m, 2H), 1.29- 1.46 (m, 2H) 14

340.2 341 2.23, V3018V3001 Method  8 ¹H NMR (400 MHz, DMSO-d₆) δ 10.06(s, 1H), 7.10-7.30 (m, 2H), 6.89 (d, J = 7.6 Hz, 1H), 6.81 (dd, J = 2.0,7.6 Hz, 1H), 6.25 (s, 1H), 5.58 (s, 2H), 4.86 (s, 2H), 3.99-4.12 (m,4H), 1.33-1.51 (m, 6H) 15

368.1 369 2.25, V3018V3001 Method  9 ¹H NMR (400 MHz, DMSO-d₆) δ 10.07(s, 1H), 6.52 (s, 1H), 6.45 (s, 1H), 6.33 (s, 1H), 6.09 (s, 1H),5.46-5.68 (m, 3H), 5.34 (dt, J = 5.2, 15.9 Hz, 1H), 4.83 (s, 2H), 4.54(d, J = 5.2 Hz, 2H), 4.24 (t, J = 5.3 Hz, 2H), 3.68 (s, 3H), 2.21- 2.31(m, 2H) 16

342.1 343 2.04, V3018V3001 Method 10 ¹H NMR (500 MHz, DMSO-d₆) δ 10.13(br. s., 1H), 7.58 (dd, J = 1.7, 7.9 Hz, 1H), 7.14 (dd, J = 8.3, 10.9Hz, 1H), 6.73-6.94 (m, 1H), 5.88-6.13 (m, 2H), 5.41-5.75 (m, 3H), 4.83(s, 2H), 4.61 (d, J = 5.4 Hz, 2H), 4.56 (d, J = 6.3 Hz, 2H) 17

342.1 343 2.04, V3018V3001 Method 10 ¹H NMR (500 MHz, DMSO-d₆) δ 11.15(br. s., 1H), 7.70 (dd, J = 1.9, 7.9 Hz, 1H), 6.96-7.53 (m, 2H),6.80-6.93 (m, 1H), 6.37 (s, 1H), 6.24 (dt, J = 6.3, 15.8 Hz, 1H), 5.63(dt, J = 5.9, 15.8 Hz, 1H), 4.77- 4.99 (m, 4H), 4.58 (d, J = 6.3 Hz, 2H)18

323.1 324 1.78, V3018V3001 Method 11 ¹H NMR (500 MHz, DMSO-d₆) δ 10.01(s, 1H), 6.93 (t, J = 7.7 Hz, 1H), 6.74 (br. s., 1H), 6.40-6.58 (m, 2H),6.30 (s, 1H), 6.02 (br. s., 1H), 5.83 (dt, J = 5.4, 16.0 Hz, 1H), 5.58(br. s., 2H), 5.36-5.50 (m, 1H), 4.74 (s, 2H), 4.49 (d, J = 5.4 Hz, 2H),3.56-3.87 (m, 2H) 19

358.1 359 2.27, V3018V3001 Method 14 ¹H NMR (500 MHz, DMSO-d₆) δ 9.49(br. s, 1H), 7.44 (d, J = 7.9 Hz, 1H), 7.14 (dd, J = 8.2, 11.4 Hz, 1H),6.84-6.97 (m, 1H), 6.34 (s, 1H), 5.69 (s, 2H), 4.84 (s, 2H), 4.03- 4.17(m, 4H), 1.31-1.57 (m, 6H) 20

358.1 359 2.27, V3018V3001 Method 14 ¹H NMR (500 MHz, DMSO-d₆) δ 11.04(br. s., 1H), 7.46 (dd, J = 1.9, 8.2 Hz, 1H), 6.86-7.32 (m, 3H), 6.78(s, 1H), 4.94 (s, 2H), 4.41 (t, J = 6.6 Hz, 2H), 4.09 (t, J = 6.9 Hz,2H), 1.63-1.73 (m, 2H), 1.53-1.62 (m, 2H), 1.36- 1.49 (m, 2H) 21

356.1 357 2.21, V3018V3001 Method 13 ¹H NMR (500 MHz, DMSO-d₆) δ 10.09(br. s., 1H), 6.99-7.23 (m, 2H), 6.92 (br. s., 1H), 6.15 (s, 1H),5.53-5.73 (m, 3H), 5.23-5.48 (m, 1H), 4.85 (s, 2H), 4.67 (d, J = 4.4 Hz,2H), 4.24 (t, J = 4.6 Hz, 2H), 2.21-2.35 (m, 2H) 22

356.1 357 2.21, V3018V3001 Method 13 ¹H NMR (500 MHz, DMSO-d₆) δ 11.11(br. s., 1H), 7.10-7.42 (m, 3H), 7.07 (dd, J = 1.9, 8.2 Hz, 1H),6.85-6.99 (m, 1H), 6.64 (s, 1H), 5.80 (dt, J = 7.2, 15.6 Hz, 1H), 5.59(dt, J = 5.7, 15.6 Hz, 1H), 4.98 (s, 2H), 4.68 (d, J = 5.7 Hz, 2H),4.41-4.59 (m, 2H), 2.38-2.50 (m, 2H) 23

325.2 326 1.83, V3018V3001 Method 12 ¹H NMR (500 MHz, DMSO-d₆) δ 9.97(br. s., 1H), 7.05 (s, 1H), 6.90 (t, J = 7.7 Hz, 1H), 6.42 (d, J = 7.7Hz, 1H), 6.38 (d, J = 7.7 Hz, 1H), 6.35 (s, 1H), 5.33- 5.58 (m, 3H),4.77 (s, 2H), 4.17 (t, J = 6.8 Hz, 2H), 3.20 (q, J = 6.4 Hz, 2H),1.42-1.52 (m, 2H), 1.32- 1.41 (m, 2H) 24

344.1 345 2.08, V3018V3001 Method 14 ¹H NMR (500 MHz, DMSO-d₆) δ 10.04(br. s., 1H), 7.77 (d, J = 7.6 Hz, 1H), 7.10 (dd, J = 8.7, 11.2 Hz, 1H),6.78 (br. s., 1H), 6.28 (s, 1H), 5.56 (s, 2H), 4.86 (s, 2H), 4.28-4.47(m, 2H), 4.04-4.23 (m, 2H), 1.52-1.66 (m, 2H), 1.31- 1.50 (m, 2H) 25

338.1 339 2.13, V3018V3001 Method 15 ¹H NMR (500 MHz, DMSO-d₆) δ 10.07(br. s., 1H), 7.18 (t, J = 7.9 Hz, 1H), 7.14 (s, 1H), 6.73- 6.87 (m,2H), 5.96 (dt, J = 5.0, 15.7 Hz, 1H), 5.90 (s, 1H), 5.57 (s, 2H), 5.37(dt, J = 5.8, 15.7 Hz, 1H), 4.86 (s, 2H), 4.58 (d, J = 5.8 Hz, 2H), 4.22(t, J = 5.0 Hz, 2H), 2.27-2.42 (m, 2H) 26

337.2 338 2.02, V3018V3001 Method 16 ¹H NMR (500 MHz, DMSO-d₆) δ 10.04(br. s., 1H), 6.95 (t, J = 7.2 Hz, 1H), 6.51 (d, J = 7.2 Hz, 1H), 6.46(dd, J = 1.3, 7.2 Hz, 1H), 6.40 (s, 1H), 6.16 (s, 1H), 5.97 (t, J = 6.3Hz, 1H), 5.59 (s, 2H), 5.43 (dt, J = 6.3, 15.5 Hz, 1H), 5.22 (dt, J =5.0, 15.5 Hz, 1H), 4.76 (s, 2H), 4.23 (t, J = 5.2 Hz, 2H), 3.56 (t, J =5.0 Hz, 2H), 2.18-2.30 (m, 2H) 27

356.1 357 2.30, V3018V3001 Method 17 ¹H NMR (500 MHz, DMSO-d₆) δ 10.11(br. s., 1H), 6.77 (d, J = 9.1 Hz, 1H), 6.71 (s, 1H), 6.63 (dt, J = 2.2,9.1 Hz, 1H), 6.15 (s, 1H), 5.64 (s, 2H), 5.57 (dt, J = 6.6, 15.8 Hz,1H), 5.34 (dt, J = 5.3, 15.8 Hz, 1H), 4.89 (s, 2H), 4.59 (d, J = 4.7 Hz,2H), 4.25 (t, J = 5.3 Hz, 2H), 2.20-2.34 (m, 2H) 28

356.1 357 2.31, V3018V3001 Method 17 ¹H NMR (500 MHz, DMSO-d₆) δ 11.09(br. s., 1H), 7.15 (br. s., 2H), 6.82 (d, J = 8.8 Hz, 1H), 6.56- 6.70(m, 3H), 5.71 (dt, J = 6.3, 15.6 Hz, 1H), 5.52 (dt, J = 5.4, 15.6 Hz,1H), 4.99 (s, 2H), 4.62 (d, J = 5.4 Hz, 2H), 4.50 (t, J = 4.7 Hz, 2H),2.42-2.47 (m, 2H) 29

337.2 338 2.05, V3018V3001 Method 16 ¹H NMR (500 MHz, DMSO-d₆) δ 10.08(br. s., 1H), 6.96 (t, J = 7.7 Hz, 1H), 6.45-6.57 (m, 2H), 6.42 (s, 1H),6.20 (s, 1H), 5.92 (t, J = 6.0 Hz, 1H), 5.65 (s, 2H), 5.31-5.48 (m, 1H),5.08-5.26 (m, 1H), 4.75 (s, 2H), 4.31 (t, J = 5.8 Hz, 2H), 3.41-3.48 (m,2H), 2.12-2.28 (m, 2H) 30

342.1 343 2.08, V3018V3001 Method 19 ¹H NMR (500 MHz, DMSO-d₆) δ 10.10(br. s., H), 7.23 (s, 1H), 6.78 (d, J = 8.8 Hz, 1H), 6.62 (d, J = 8.8Hz, 1H), 6.08 (s, 1H), 5.84 (dt, J = 5.0, 15.8 Hz, 1H), 5.71 (dt, J =5.0, 15.8 Hz, 1H), 5.60 (s, 2H), 4.86 (s, 2H), 4.63 (d, J = 5.0 Hz, 2H),4.54 (d, J = 5.0 Hz, 2H) 31

342.1 343 2.08, V3018V3001 Method 19 ¹H NMR (500 MHz, DMSO-d₆) δ 11.12(br. s., 1H), 7.34 (s, 1H), 7.15 (br, s., 2H), 6.85 (d, J = 10.4 Hz,1H), 6.64 (d, J = 10.4 Hz, 1H), 6.44 (s, 1H), 6.07 (dt, J = 5.9, 15.8Hz, 1H), 5.70 (dt, J = 5.9, 15.8 Hz, 1H), 4.95 (s, 2H), 4.84 (d, J = 5.9Hz, 2H), 4.64 (d, J = 5.9 Hz, 2H) 32

358.1 359 2.32, V3018V3001 Method 18 ¹H NMR (500 MHz, DMSO-d₆) δ 10.13(br. s., 1H), 7.05 (s, 1H), 6.71 (d, J = 9.1 Hz, 1H), 6.67 (d, J = 9.1Hz, 1H), 6.28 (s, 1H), 5.63 (s, 2H), 4.87 (s, 2H), 3.85-4.18 (m, 4H),1.21- 1.59 (m, 6H) 33

344.1 345 2.14, V3018V3001 Method 14 ¹H NMR (500 MHz, DMSO-d₆) δ 10.09(br. s., 1H), 7.33 (s, 1H), 6.66 (d, J = 9.1 Hz, 1H), 6.59 (d, J = 9.1Hz, 1H), 6.17 (s, 1H), 5.58 (s, 2H), 4.90 (s, 2H), 4.29 (t, J = 6.5 Hz,2H), 4.15 (t, J = 6.5 Hz, 2H), 1.48-1.59 (m, 2H), 1.36- 1.46 (m, 2H) 34

339.2 340 2.06, V3018V3001 Method 12 ¹H NMR (500 MHz, DMSO-d₆) δ 10.05(s, 1H), 6.83-7.00 (m, 1H), 6.62 (s, 1H), 6.50 (d, J = 8.2 Hz, 1H), 6.43(dd, J = 1.6, 8.2 Hz, 1H), 6.36 (s, 1H), 5.72 (t, J = 6.6 Hz, 1H), 5.60(s, 2H), 4.76 (s, 2H), 4.07 (t, J = 5.7 Hz, 2H), 2.95 (q, J = 6.6 Hz,2H), 1.12-1.50 (m, 8H) 35

338.1 339 1.97, V3018V3001 Method 20 ¹H NMR (500 MHz, DMSO-d₆) δ 9.92(br. s., 1H), 6.81-7.02 (m, 2H), 6.73 (d, J = 8.2 Hz, 1H), 6.38 (d, J =8.2 Hz, 1H), 5.91 (dt, J = 4.4, 16 Hz, 1H), 5.38-5.57 (m, 3H), 5.33 (s,1H), 4.65 (d, J = 4.4 Hz, 2H), 4.54 (d, J = 4.4 Hz, 2H), 3.96 (t, J =5.2 Hz, 2H), 2.87 (t, J = 5.2 Hz, 2H) 36

368.1 369 1.86, V3018V3001 Method 20 ¹H NMR (500 MHz, DMSO-d₆) δ 9.92(br. s., 1H), 7.01 (s, 1H), 6.60 (d, J = 8.2 Hz, 1H), 6.36 (d, J = 8.2Hz, 1H), 6.02 (dt, J = 5.0, 16 Hz, 1H), 5.46 (s, 2H), 5.28-5.42 (m, 2H),4.61 (d, J = 5.0 Hz, 2H), 4.52 (d, J = 5.0 Hz, 2H), 3.77-4.04 (m, 2H),3.65 (s, 3H), 2.70-2.91 (m, 2H)Biological Activity of Compounds of Formula (I)Description of Biological AssaysAssessment of TLR7 and TLR8 Activity

The ability of compounds to activate human TLR7 and TLR8 was assessed ina cellular reporter assay using HEK293 cells transiently transfectedwith a TLR7 or TLR8 expression vector and NFκB-luc reporter construct.Briefly, HEK293 cells were grown in culture medium (DMEM supplementedwith 10% FCS and 2 mM Glutamine). For transfection of cells in 15 cmdishes, cells were detached with Trypsin-EDTA, transfected with a mix ofCMV-TLR7 or TLR8 plasmid (1,700 ng), NFκB-luc plasmid (850 ng) and atransfection reagent and incubated 48 hours at 37° C. in a humidified 5%CO₂ atmosphere. Transfected cells were then washed in PBS, detached withTrypsin-EDTA, and resuspended in medium to a density of 1.25×10⁵cells/mL. Forty microliters of cells were then dispensed into each wellin 384-well plates, where 200 nL of compound in 100% DMSO was alreadypresent. Following 6 hours incubation at 37° C., 5% CO₂, the luciferaseactivity was determined by adding 15 μl of Steady Lite Plus substrate(Perkin Elmer) to each well and readout performed on a ViewLux ultraHTSmicroplate imager (Perkin Elmer). Dose response curves were generatedfrom measurements performed in quadruplicates. Lowest effectiveconcentrations (LEC) values, defined as the concentration that inducesan effect which is at least two fold above the standard deviation of theassay, were determined for each compound.

In parallel, a similar dilution series of compound was used (200 nL ofcompound in 100% DMSO) with 40 μL per well of cells transfected withNFκB-luc reporter construct alone (1.25×10⁵ cells/mL). Six hours afterincubation at 37° C., 5% CO₂, the luciferase activity was determined byadding 15 μl of Steady Lite Plus substrate (Perkin Elmer) to each welland readout performed on a ViewLux ultraHTS microplate imager (PerkinElmer). Counterscreen data is reported as LEC.

Measurement of Interferon Production in Human PBMC

Activation of human TLR7 results in robust production of interferon byplasmacytoid dendritic cells present in human blood. The potential ofcompounds to induce interferon was evaluated by determination ofinterferon in the conditioned media from peripheral blood mononuclearcells (PBMC). The presence of interferon in the samples was determined,using an interferon reporter cell line stably expressing aninterferon-stimulated responsive elements (ISRE)-luc reporter construct.The ISRE element with sequence TAGTITCACTITCCC (SEQ. ID. NO:1) is highlyresponsive to the STAT1-STAT2-IRF9 transcription factor, which becomesactivated upon binding of IFN-I to the IFN receptor. Briefly, PBMCs wereprepared from buffy coats of at least two donors using a standard Ficollcentrifugation protocol. Isolated PBMCs were resuspended in RPMI mediumsupplemented with 10% human AB serum and 2×10⁵ cells/well were dispensedinto 384-well plates containing compounds (70 jgL total volume). Afterovernight incubation of 10 the PBMCs with the compounds, 10 μL ofsupernatant was transferred to 384-well plates containing 5×10HEK-ISRE-luc cells/well in 30 μL (plated the day before). Following 24hours of incubation, activation of the ISRE elements was measured byassaying luciferase activity using 40 μL/well Steady Lite Plus substrate(Perkin Elmer) and measured with ViewLux ultraHTS microplate imager(Perkin Elmer). The stimulating activity of each compound on theHEK-ISRE-luc cells was reported as LEC. The LEC in turn indicates thedegree of ISRE activation on transfer of a defined amount of PBMCculture medium. Recombinant interferon alfa-2a (Roferon-A) was used as astandard control compound.

The LEC values for the compounds in table 2 on HEK293 TLR8-NFκB-luc andHEK293 NFκB-luc where greater than the highest tested concentration (>10μM for compound 4 and >25 μM for all other compounds).

TABLE 2 Compounds of formula (I) n represents the number of experimentsperformed. HEK293 PBMC TLR7-NFκB-luc HEK-ISRE-luc # STRUCTURE (LEC; μM)n (LEC; μM) n  1

2.88 8 0.30 8  2

4.47 1 0.93 2  3

0.27 2  0.033 4  4

2.38 1 2.56 2  5

2.14 1  0.082 2  6

1   1 0.16 2  7

3.88 1 0.29 2  8

7.1  1 0.58 2  9

11.09  1 10.87  2 10

0.78 2 0.25 4 11

1.25 1 0.45 2 12

1.08 1 0.3  2 13

1.71 2 0.15 2 14

7.01 2 2.4  2 15

0.18 1 0.04 2 16

2.02 2 0.47 2 17

1.88 2 0.39 4 18

8.02 1 1.11 2 19

14.96  2 2.22 4 20

4.99 1 1.61 2 21

0.9  1 0.25 3 22

1.83 1 0.39 2 23

16.74  2 8.98 4 24

2.14 4 25

1.92 1 0.53 2 26

1.88 2 0.37 4 27

1.35 1 0.14 2 28

0.91 1 0.15 2 29

1.14 2 0.48 2 30

0.64 1 0.15 2 31

1.19 1 0.15 2 32

2.92 2 0.49 2 33

2.77 1 0.45 2 34

8.1  2 2.11 2 35

17.43  1 1.98 2 36

13.75  1 1.63 4

The invention claimed is:
 1. A compound of formula (I):

or a pharmaceutically acceptable salt thereof, wherein: n is 1, 2, or 3; X is selected from the group consisting of oxygen, NH, and sulfur; Y is phenyl or pyridyl, optionally substituted by one or more substituents independently selected from the group consisting of C₁₋₆alkyl, C₁₋₄alkoxy, trifluoromethyl, and halogen; and Z is selected from the group consisting of C₁₋₁₀ alkyl, C₁₋₆alkyl-NH—C(O)—C₁₋₆alkyl-, —C₁₋₆ alkyl-NH—, —C₁₋₆alkyl-NH—C(O)—C₁₋₆alkyl-O—, —C₁₋₁₀alkyl-O—, —C₁₋₆alkyl-O—C₁₋₆alkyl-, and —C₁₋₆alkyl-O—C₁₋₆alkyl-O—, wherein said alkyl is unsaturated or saturated and can optionally be substituted by an alkyl or alkylhydroxyl.
 2. A pharmaceutical composition comprising a compound of claim 1 or a pharmaceutically acceptable salt thereof, together with one or more pharmaceutically acceptable excipients, diluents, or carriers.
 3. A method of activating TLR7 in a subject, comprising administering a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim
 1. 4. A method of inducing interferon production in a subject, the method comprising administering a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim
 1. 5. The compound of claim 1, wherein n is 1 or
 2. 6. The compound of claim 1, wherein Y is phenyl optionally substituted with methoxy or fluorine.
 7. The compound of claim 1, wherein Y is pyridinyl.
 8. The compound of claim 1, wherein Z is C₁₋₁₀ alkyl, and wherein said alkyl is unsaturated or saturated.
 9. The compound of claim 1, wherein Z is —C₁₋₆ alkyl-NH—, and wherein said alkyl is unsaturated or saturated.
 10. The compound of claim 1, wherein Z is —C₁₋₁₀alkyl-O—, and wherein said alkyl is unsaturated or saturated.
 11. The compound of claim 1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 12. The compound of claim 1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 13. The compound of claim 1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 14. The compound of claim 1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 15. The compound of claim 1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 16. The compound of claim 1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 17. The compound of claim 1, wherein the compound is:

or a pharmaceutically acceptable salt thereof. 